Eating disorders - Biology of appetite and weight regulation
*Biochemical:Eating behavior is a complex process controlled by the neuroendocrine system of which the Hypothalamus-pituitary-adrenal-axis (HPA axis) is a major component. Dysregulation of the HPA-axis has been associated with eating disorders,Gross MJ Corticotropin-releasing factor and anorexia nervosa: reactions of the hypothalamus-pituitary-adrenal axis to neurotropic stressAnn Endocrinol (Paris). 1994;55(6):221-8. PMID 7864577Licinio J, Wong ML,The hypothalamic-pituitary-adrenal axis in anorexia nervosa. Gold PW.Psychiatry Res. 1996 Apr 16;62(1):75-83.PMID 8739117 such as irregularities in the manufacture, amount or transmission of certain neurotransmitters, hormonesChaudhri O, Small C, Bloom S. Gastrointestinal hormones regulating appetite. Philos Trans R Soc Lond B Biol Sci. 2006 Jul 29;361(1471):1187-209. PMID 16815798 or neuropeptidesGendall KA.Leptin, neuropeptide Y, and peptide YY in long-term recovered eating disorder patients. Biol Psychiatry. 1999 Jul 15;46(2):292-9. PMID 10418705. **serotonin: a neurotransmitter involved in depression also has an inhibitory affect on eating behaviorJimerson DC, et.al.,Eating disorders and depression: is there a serotonin connection? Biol Psychiatry. 1990 Sep 1;28(5):443-54. PMID 2207221Leibowitz, The role of serotonin in eating disorders. Drugs 1990;39Suppl 3:33-44 PMID 2197074Blundell et al.''serotonin, eating behavior, fat intake Obes Res 1995 Nov;3 Suppl4:471s-476s PMID 8697045Kaye WH, Anorexia, obsessional behavior and serotonin, Psycopharmacology Bulletin 1997;33(3)335-44 PMID 9550876Bailer UF ''et al.''Altered 5-HT(2A) receptor binding after recovery from bulimia-type anorexia nervosa: relationships to harm avoidance and drive for thinness. Neuropsychopharmacology. 2004 Jun;29(6):1143-55. PMID 15054474 **norepinephrine is both a neurotransmitter and a hormone; abnormalities in either capacity may affect eating behaviorHainer V ''et al.,Serotonin and norepinephrine reuptake inhibition and eating behavior. Annals of The New York Academy of Sciences 2006 Nov;1083:252-69 PMID 17148744Altered norepinephrine in bulimia: effects of pharmacological challenge with isoproternol Psychiatric Residency 1990 Jul;33 (1):1PMID 2171006 **dopamine:which in addition to being a precursor of norepinephrine and epinephrine is also a neurotransmitter which regulates the rewarding property of foodWang et, al. Brain dopamine and obesity Lancet 2001 Feb. 3;357(9253):354-357 PMID 11210998Volknow et al. ''Brain dopamine is associated with eating behavior in humans International Journal of Eating Disorder 2003 Mar:33 (2)136-42 PMID 1216579 *leptin and ghrelin; leptin is a hormone produced primarily by the fat cells in the body it has an inhibitory effect on appetite by inducing a feeling of saiety. Ghrelin is an appetite inducing hormone produced in the stomach and the upper portion of the small intestine. Circulating levels of both hormones are an important factor in weight control. While often associated with obesity both hormones and their respective effects have been implicated in the pathophysiology of anorexia nervosa and bulimia nervosa.Frederich R, Hu S, Raymond N, Pomeroy C. Leptin in anorexia nervosa and bulimia nervosa: importance of assay technique and method of interpretation. PMID 11919545 *immune system:studies have shown that a majority of patients with anorexia and bulimia nervosa have elevated levels of autoantibodies that affect hormones and neuropeptides that regulate appetite control and the stress response. There may be a direct correlation between autoantibody levels and associated psychological traits.Fetissov SO ''et al.''Autoantibodies against neuropeptides are associated with psychological traits in eating disorders. Proc Natl Acad Sci U S A. 2005 Oct 11;102(41):14865-70. Epub 2005 Sep 29.PMID 16195379Sinno MH.''et al. Regulation of feeding and anxiety by alpha-MSH reactive autoantibodies. Psychoneuroendocrinology. 2009 Jan;34(1):140-9. Epub 2008 Oct 8.PMID 18842346 *infection:PANDAS, is an abbreviation for Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections. Children with PANDAS "have Obsessive Compulsive Disorder (OCD) and/or tic disorders such as Tourette's Syndrome, and in whom symptoms worsen following infections such as "Strep throat" and Scarlet Fever." (NIMH) There is a possibility that PANDAS may be a precipitating factor in the development of Anorexia nervosa in some cases, (PANDAS AN).Sokol MS. Child Adolesc Psychopharmacol. 2000 Summer;10(2):133-45.Infection-triggered anorexia nervosa in children: clinical description of four cases. PMID 10933123 *lesions:studies have shown that lesions to the right frontal lobe or temporal lobe can cause the pathological symptoms of an eating disorderUher R, Treasure J. Brain lesions and eating disorders. J Neurol Neurosurg Psychiatry. 2005 Jun;76(6):852-7. PMID 15897510Houy E et al.''Anorexia nervosa associated with right frontal brain lesion. Int J Eat Disord. 2007 Dec;40(8):758-61. PMID 17683096Trummer M ''et al.,Right hemispheric frontal lesions as a cause for anorexia nervosa report of three cases Acta Neurochir (Wien). 2002 Aug;144(8):797-801; discussion 801. PMID 12181689 *tumors:tumors in various regions of the brain have been implicated in the development of abnormal eating patterns.Winston AP Pineal germinoma presenting as anorexia nervosa: Case report and review of the literature. Int J Eat Disord. 2006 Nov;39(7):606-8. PMID 17041920Chipkevitch E, Fernandes AC. Hypothalamic tumor associated with atypical forms of anorexia nervosa and diencephalic syndrome. Arq Neuropsiquiatr. 1993 Jun;51(2):270-4. PMID 8274094Rohrer TR et al.''Craniopharyngioma in a female adolescent presenting with symptoms of anorexia nervosa. Klin Padiatr. 2006 Mar-Apr;218(2):67-71. PMID 16506105Chipkevitch E. Brain tumors and anorexia nervosa syndrome. Brain Dev. 1994 May-Jun;16(3):175-9, discussion 180-2.PMID 7943600Lin L ''et al. Brain tumor presenting as anorexia nervosa in a 19-year-old man. J Formos Med Assoc. 2003 Oct;102(10):737-40. PMID 14691602 *brain calcification: a study highlights a case in which prior calcification of the right thalumus may have contributed to development of anorexia nervosa.Conrad R et al. Nature against nurture, calcification in the right thalamus in a young man with anorexia nervosa and obsessive compulsive personality-disorder CNS Spectrum 2008 Oct;13(10)906-10 PMID 18955946 *somatosensory homunculus; is the representation of the body located in the somatosensory cortex, first described by renowned neurosurgeon Wilder Penfield. The illustration was originally termed "Penfield's Homunculus", homunculus meaning little man. "In normal development this representation should adapt as the body goes through its pubertal growth spurt. However, in AN it is hypothesized that there is a lack of plasticity in this area, which may result in impairments of sensory processing and distortion of body image". (Bryan Lask, also proposed by VS Ramachandran) *Obstetric complications. There have been studies done which show maternal smoking, obstetric and perinatal complications such as maternal anemia, very pre-term birth (32Burke CJ, Tannenberg AE, Payton DJ Ischaemic cerebral injury, intrauterine growth retardation, and placental infarction. Dev Med Child Neurol. 1997 Nov;39(11):726-30.PMID 9393885Cnattinghuis S et.al. Very pre-term birth, birth trauma and the risk of anorexia nervosa among girls. Arch Gen Psychiatry 1999 Jul;56(7):634-8PMID 10401509Favoro A et al. Perinatal factors and the risk of developing anorexia nervosa and bulimia nervosa Arch Gen Psychiatry 2006 Jan;63(1)82-8. PMID 16389201Favoro A The relationship between obstetric complications and temperament in eating disorders:a mediation hypothesis Psychosom Med 2008 Apr.70(3):372-7 PMID 18256341Decker MJ et al.''Episodic neonatal hypoxia evokes executive dysfunction and regionally specific alterations in markers of dopamine signaling. Neuroscience. 2003;117(2):417-25. PMID 12614682Decker MJ, Rye DB.Neonatal intermittent hypoxia impairs dopamine signaling and executive functioning. Sleep Breath. 2002 Dec;6(4):205-10. PMID 12524574Scher MS.Fetal and neonatal neurologic case histories: assessment of brain disorders in the context of fetal-maternal-placental disease. Part 1: Fetal neurologic consultations in the context of antepartum events and prenatal brain development. J Child Neurol. 2003 Feb;18(2):85-92. PMID 12693773Scher MS, Wiznitzer M, Bangert BA.Cerebral infarctions in the fetus and neonate: maternal-placental-fetal considerations. Clin Perinatol. 2002 Dec;29(4):693-724, vi-vii. PMID 12516742Burke CJ, Tannenberg AEDev Med Child Neurol. 1995 Jun;37(6):555-62. Prenatal brain damage and placental infarction--an autopsy study. PMID 7789664Squier M, Keeling JW.The incidence of prenatal brain injury. Neuropathol Appl Neurobiol. 1991 Feb;17(1):29-38. PMID 2057048Al Mamun A et.''al. Does maternal smoking during pregnancy have a direct effect on future offspring obesity? Evidence from a prospective birth cohort study. Am J Epidemiol. 2006 Aug 15;164(4):317-25. PMID 16775040 See also *Appetite References Category:Eating disorders